The Deus coils are in fact waterproof, it's just the wireless signal from the coil to the headphones or control box that is compromised underwater without the optional aerial kit. So it should be fine for dry/wet sand duties at the beach, just not underwater - there are more appropriate detectors for that task vs a VLF (for beaches). As for the charging contacts, they should be fine if washed off under fresh water after any beach outings, just as you should do with any other detector coil in such circumstances. A small tab of electrical tape over the contacts will also help protect them.
Every time the Deus is upgraded, all that is required is a free download from XP's website,. No more having manufacturers forcing you to upgrade detectors to get the latest features, drip feeding you minor improvements at a substantial cost on what they claim are "new" detectors.
If on a tighter budget, I probably would have opted for a Racer or Core.
Ok, it's a bit long winded, but here's my take on the Deus so far:
Regarding repairs on the Deus, I'm not too fussed on Oz warranties/servicing going by past experiences, aside from that, the service I received so far from XP France and related retailers was excellent. What is unique to the Deus, and more important to me, is that I can literally purchase any replacement part for this detector, and see it here in a bit over a week from France. I can't think of any other detector manufacturer where this is possible. No more wasting time waiting for dealers getting their act together ordering parts at their convenience.
If you do need to send in the control box for warranty repairs, the headphones can be used to control the detector in the meantime, or use the control box if the wireless headphone module requires repairs. No need to send the whole detector off for repairs.
If you purchase a second coil and shaft, you instantly have two Deus detectors - one can run off the headphones, whilst the other is operated via the main control box. If it rains, take the control box off, and just use the shaft, coil and headphones (the headphones are weatherproof). The main control box is fully upgradable via USB, has a loud inbuilt speaker, small headphone jack, backlit screen, and as soon as you turn it off, the headphones take over as the main controller for the detector.
The sheer amount of adjustments you can make on this detector really is astounding. Though it can also be very simple to use via one of the several inbuilt programs. These can be easily customised, renamed, and saved to a new slot for future use. There are four frequencies to play with at the press of a button, no need to change coils, and battery power will last for days on a single charge of the lithium batteries. You do not require a 240v power source to charge the detector, all can be done via any USB port or portable power source, and charging time is a also very short compared to your regular Nicad battery packs on other detectors.
As for ground balancing, you can chose auto tracking, pump (ground grab), beach or manual adjustment, most of the time manual adjustment is the best to use, especially in junky areas. The manual adjustment has a fair bit of resolution to it, so accurate adjustments can be made.
This is by far the lightest detector I have ever used, even lighter than a stock Ace 250 (1.2 kg) by 213 grams, 313 grams lighter with the control box removed. Even with the larger 11"coil, it still weighs 150 grams lighter than the Ace. For comparison, the Makro Racer weighs 1.4 kg, the Fors Core heavier again at 1.6 kg, and the Etrac at well over 2kg.
This ultimately has a huge effect on the enjoyment of detecting, and how much ground you can reasonably expect to cover within a given amount of time. Sorry Minelab, might be a good time to invest in Lithium batteries for your coin/relic detectors to get the weight down. :|
For gold detecting there is a separate program to suit such activities. The pinpoint button is now allocated as a ground grab button, frequency is set on 17kHz, and from what I have seen so far, it operates quite nicely in the GT from a few trials last weekend, certainly a lot better than my G2 (Goldbug2). Also included is a feature to discriminate out hot rocks, plus you have the choice to use the lower frequencies to search for deeper gold, whilst handling mineralisation better than the 17kHz frequency.
You do have to keep in mind that these are tone based detectors, so they will not get accurate TID's on deeper targets like a CTX, hence you will be relying more on tones to pick out desirable targets. Either way, it is preferable that you would want an excuse to dig rather than not to dig, so TID's can be a hindrance in that respect.
The mode/program I current use is called fulltones, which is essentially a sliding scale of tones depending on the conductivity of the target. You also get the choice of using 5, 4, 3, and 2 tones, and pitch mode which is similar to a VCO response, but based on depth not conductivity.
There are so many things to like about this detector, I honestly struggle to find much wrong with it so far. A minor criticism regarding the lightweight wireless headphones is that they can be a bit sharp around the back of your ears after long periods. I was going to criticise the pricing, but I honestly believe in this case you get what you pay for.